[Healeys] Denis Welch Tappets Again

[richard mayor]

Forgive my ignorance here but I have never heard of a cam being “hardened”.  As racer for many years and with many race engine builds under my belt I have had cams and lifters (and many other engine parts) cryogenically treated. 

I know cranks are hardened by nitriding.  But I’ve never know anyone to nitride a cam. 


Richard Mayor
boyracer466 at gmail.com



> On May 24, 2023, at 1:08 PM, Michael MacLean <springer.mike51 at gmail.com> wrote:
> 
> This thread got me thinking.  I had the cam ground at a reputable cam grinder locally. (Web Cams) They have been grinding cams for Healeys since the 60s.  I just got off the phone with them and asked if they had hardened the lobes of the cam they ground for me.  When they looked it up the paperwork showed the cam was simply ground, not hardened.  They will harden it for $50.  Of course it has to come out of the assembled engine first.  Also Michael, the very experienced Healey engine builder that built my short block, who has since passed away, told me to use the old used springs for the valves.  He said it would tick over nicely at 700 rpm.  Of course through conflicting information I installed new double springs.   I still have the old springs.  As long as I will be taking this all apart again, I might as well put just the outer set of used springs back on the head.
> Mike MacLean
> 
> On Wed, May 24, 2023 at 6:47 AM Michael Salter <michaelsalter at gmail.com <mailto:michaelsalter at gmail.com>> wrote:
>> Speaking as someone who has over the years had 2 bouts of tappet failure in 100 engines I would suggest that you are wise to be cautious.
>> I can't advise on the tappets that you have fitted but can say the I am now using sets from A H Spares which are proving to be very satisfactory and are different from those I have had problems with.
>> I have, in B.#174, a magnetic oil drain plug and have found that to be a very good indicator of impending tappet failure. On the last 2 oil changes there was absolutely no metal on the plug.
>> My procedure initial start procedure was to firstly remove the inner valve springs as I have found that they and the additional pressure that they produce are just not required as my engine exhibits absolutely no sign of valve bounce right up to the red line.
>> I use Lucas 20/50 break in oil for the 1st 500 miles. 
>> On first start I held the engine around 1500 RPM for about 20 minutes. (I have difficulty believing that this is necessary but that's what the experts recommend so you have to be sure that the cooling system is in good shape).
>> I change to VR1 non synthetic 20/50 after 500 odd miles and then change the oil every 3000 miles.
>> The engine in B#174 now runs with absolutely NO tappet clatter which is pretty unusual for a 100.
>> I recently checked the valve clearances and they were unchanged after 2500 miles, another good indicator that the cam and tappets are holding up well.
>> I'm sure others have had different experiences but I  would recommend that you make every effort to avoid a cam/tappet failure because rectification requires a complete engine strip down.
>> Good luck.
>> 
>> M
>>  (Still running perfectly with outer springs only)
>> 
>> On Wed., May 24, 2023, 8:46 a.m. Michael MacLean, <springer.mike51 at gmail.com <mailto:springer.mike51 at gmail.com>> wrote:
>>> As I get closer to starting my 100 engine I have yet to replace the modified Denis Welch tappets like a list member suggested I do.  I got nervous, so I ordered a set of NOS tappets from Ahead4Healeys to swap with the installed Welch tappets recently.  Now, searching the archives, I  find someone had problems with NOS lifters after 6000 miles. Ruined a cam and the lifters.  So, what am I supposed to do now?  Should I just buy aftermarket tappets?  Are the aftermarket tappets hardened correctly?  Why wouldn't the NOS tappets be hardened right?  I don't want to replace the cam after I get this thing running.
>>> Mike MacLean
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